This invention relates to the field of machine design, more specifically to an improved variable ratio power transmission mechanism.
Many such mechanisms are known. A frequent expedient is to provide first, driving and driven members interconnected by a further, coupling member movable to contact at least one of the first members at sites of different radius. Such contact between two cones is taught by Schott U.S. Pat. No. 3,698,255, between two discs by Whitmore U.S. Pat. No. 2,469,673 and between a cylinder and a disc by Weiss U.S. Pat. No. 2,503,310. In these prior art structures there is always a difficulty in adjusting the pressure applied by the coupling member, to insure rolling contact without slipping of the coupling member, at one extreme, or brinelling of one of the first members or crushing of the coupling member, at the other extreme. The prior art devices are also reversible, that is, they respond equally well to movement of the driving member in either direction. If it is desired to have a mechanism operate in only one sense, an additional overrunning clutch or similar mechanism must be employed.